Add 21 missing SysAbi exports and GUI Environment tab for SHARPEMU_* toggles (#189)

Fills NID gaps hit by PS5 titles during boot, controller setup, and
rendering, and surfaces the common runtime switches in the GUI. All
exports are additive (no behavior change to existing exports) and free of
NID and export-name collisions with upstream.

New export libraries:
- libSceBluetoothHid: Init/RegisterDevice/RegisterCallback success stubs so
  titles proceed past Bluetooth controller setup (opt-out via
  SHARPEMU_BTHID_UNAVAILABLE=1).
- libSceNpCppWebApi: Common::initialize no-op success; UE5 online titles
  abort PS5-component startup on a negative SCE error.

Additions to existing libraries:
- libScePad: scePadOpenExt (shared PadOpenCore, accepts special ports 1/2 and
  the ScePadOpenExtParam pointer), scePadClose, scePadGetExtControllerInformation.
- libSceVideoOut: sceVideoOutConfigureOutput, sceVideoOutInitializeOutputOptions.
- libSceAgc: DCB builders sceAgcDcbSetIndexCount, sceAgcDcbJump, DcbSetPredication,
  SetPacketPredication (emit valid skippable packets; full draw processing TODO).
- libSceAmpr: measure and write KernelEventQueueOnCompletion pair.
- libKernel: scePthreadGet/Setschedparam, sceKernelChmod (validate and accept;
  POSIX permission bits have no host equivalent on Windows).
- libSceNetCtl: sceNetCtlRegisterCallbackV6 (delegates to the v4 callback).
- libSceMouse: sceMouseInit.
- libSceUserService: sceUserServiceGetAgeLevel (adult, skips parental gates).

GUI: new Options Environment tab exposing common SHARPEMU_* switches as
toggles (BTHID_UNAVAILABLE, DISABLE_IMPORT_LOOP_GUARD, VK_VALIDATION,
DUMP_SPIRV, LOG_DIRECT_MEMORY, LOG_NP). Persisted in gui-settings.json and
applied to the emulator process environment at launch; localized with
English fallback.

src/SharpEmu.GUI/Languages/en.json

@@ -26,6 +26,15 @@
   "Library.Loading": "Loading library…",
 
   "Options.General": "General",
+  "Options.Env.Tab": "Environment",
+  "Options.Section.Environment": "ENVIRONMENT VARIABLES",
+  "Options.Env.Desc": "Switches passed to the emulator as environment variables at launch.",
+  "Options.Env.Bthid.Desc": "Report Bluetooth HID as unavailable for titles whose wheel/FFB middleware polls forever.\nLeave off normally. Some titles freeze when init fails.",
+  "Options.Env.LoopGuard.Desc": "Do not force quit titles that repeat the same call for too long.\nTry this when a game exits on its own while loading.",
+  "Options.Env.VkValidation.Desc": "Enable Vulkan validation layers for GPU debugging.\nSlow. Requires the Vulkan SDK to be installed.",
+  "Options.Env.DumpSpirv.Desc": "Dump AGC shaders and their SPIR-V translations to the shader-dumps folder.\nUse when reporting shader or rendering bugs.",
+  "Options.Env.LogDirectMemory.Desc": "Log direct memory allocations and failures to the console.\nUse when a game aborts or exits during boot.",
+  "Options.Env.LogNp.Desc": "Log NP (PlayStation Network) library calls to the console.",
   "Options.Section.Emulation": "EMULATION",
   "Options.Section.Logging": "LOGGING",
   "Options.Section.Launcher": "LAUNCHER",